This disclosure relates to liquid crystal displays (LCDs) in general, and in particular, to methods and apparatus for simultaneously forming LCD panel alignment layers and integral column spacers with a non-photolithographic patterning process.
In an effort to address the relatively large size and weight penalties of conventional Cathode Ray Tube (CRT) displays, a variety of flat panel display types, including LCDs, plasma display panels (PDPs), field emission displays (FEDs), and light emitting diode displays (LEDDs) have recently been researched and developed as substitutes therefor, all of which are thinner, lighter and occupy less volume than comparable CRT displays.
The display panel of an LCD produces an image by adjusting the light transmittance of the molecules of a layer of liquid crystal material disposed between two substrates of the panel. The LCD panel is formed by bonding a color filter substrate, having a color filter array disposed thereon, to a thin film transistor (TFT) substrate, having a TFT array comprising a plurality of transistors and signal lines disposed thereon, with the layer of liquid crystal material being sandwiched between the two substrates. Each of the two substrates is respectively coated with an alignment layer, and a “cell gap” created between the two substrates to contain the liquid crystal layer is defined and maintained by a plurality of column spacers disposed therebetween.
In conventional LCD manufacturing techniques, the column spacers are formed by a photolithography process, which includes steps involving photoresist coating, mask alignment, exposure and development, and stripping.
However, the photolithography process has a number of drawbacks, including that it requires a long time to complete, is wasteful of the photoresist stripping solution, and requires large, expensive photolithography equipment, the size and cost of which escalate dramatically as LCD panel sizes increase and pattern sizes decrease.